$$
\begin{aligned}
&{[\mathrm{P}] \stackrel{\mathrm{Br}_{2}}{\longrightarrow} \mathrm{C}_{2} \mathrm{H}_{4} \mathrm{Br}_{2} \underset{\mathrm{NH}_{3}}{\stackrel{\mathrm{NaNH}_{2}}{\longrightarrow}}[\mathrm{Q}]} \\
&{[\mathrm{Q}] \stackrel{20 \% \mathrm{H}_{2} \mathrm{SO}_{4}}{\mathrm{Hg}^{2}+\Delta}[\mathrm{R}] \stackrel{\mathrm{Zn}-\mathrm{Hg} / \mathrm{HCl}}{\longrightarrow}[\mathrm{S}]}
\end{aligned}
$$
The species \(\mathrm{P}, \mathrm{Q}, \mathrm{R}\) and \(\mathrm{S}\) respectively are
(A) ethene, ethyne, ethanal, ethane
(B) ethane, ethyne, ethanal, ethene
(C) ethene, ethyne, ethanal, ethanol
(D) ethyne, ethane, ethene, ethanal
Ans: (A)
